Crystallization and preliminary X-ray analysis of pseudo-merohedrally twinned crystals of the full-length β2 subunit of the Kv1 K+ channel from Rattus norvegicus
Authors: Shimamura, Tatsuro; Shamotienko, Oleg; Akhtar, Sobia; Dolly, J. Oliver; Iwata, So
Source: Acta Crystallographica Section D, Volume 60, Number 5, May 2004 , pp. 912-914(3)
Publisher: Blackwell Publishing
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Abstract:
The eukaryotic Kv1 voltage-gated K+ channel is composed of four α subunits and four β subunits. The full-length β2 subunit from Rattus norvegicus has been expressed in Esherichia coli, purified and then crystallized. A careful molecular-replacement study using the structure of the truncated β2 subunit reveals that the crystals are perfectly pseudo-merohedrally twinned. While the apparent space group of the crystals was P4212, the real space group was shown to be P21212, with unit-cell parameters a = 222.6, b = 222.6, c = 82.3 Å. An asymmetric unit of the crystal contains two β2 tetramers (MW = 340 kDa). A data set was collected from a crystal to 2.0 Å resolution, with 266 659 independent observations (93.0% complete) and Rmerge = 0.06. Although the crystals are perfectly twinned, they are still suitable for structural determination by molecular replacement using the truncated β2-subunit structure.Keywords: K+ channels; pseudo-merohedral twinning
Document Type: Research article
DOI: 10.1107/S0907444904004536
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